Modular window film application system reveals high precision, throughput
PDS IG Equipment doubles window film throughput compared to the industry standard by using EtherCAT and PC-based control.
- PDS IG created a modular automated machine to protect insulating glass (IG) units of all sizes during manufacturing, shipping and installation.
- They used industrial PCs, servomotors and EtherCAT technology to improve cycle times, productivity and innovation.
Automation programming software and an industrial PC-based control architecture helped with a high-throughput, modular machine design doubling throughput. “During construction projects, glass windows face significant risks from splashing concrete, dirt, debris and other hazards, such as tradespeople carrying tools and materials,” said Michael Rapp, vice president of sales and part-owner of PDS IG Equipment. “Applying window film during the manufacturing process not only protects the window, but it also allows contractors to simply peel off anything that might have stuck to it.”
To ensure the polyester (PET) film is applied with high repeatability, short cycle times and robust data acquisition capabilities, PDS IG created a modular automated solution to protect insulating glass (IG) units of all sizes during manufacturing, shipping and installation.
The PDS IG Equipment technology portfolio includes a broad range of window production machinery.
PDS IG built its window film application system after recognizing a lack of efficient automated systems for the process, which is nearly impossible to complete manually. Beyond offering high throughput, the modular machine design allowed greater control and flexibility for facilities operators and managers.
Machine design system requirements
The system uses multiple modules, beginning with an intake conveyor module. Operators or robots carefully load glass onto the conveyor, which transports each piece into the film applicator module. During this process, the machine measures each insulating glass unit individually, according to Steve Polkinghorne, automation controls engineer at PDS IG. “The machine measures the length by taking a position latch of the rising edge and the falling edge as the units enter, and it uses a measurement sensor for the height,” he said. “Then while applying the film, the machine takes a high-speed snapshot of the unit’s position relative to the axis position to fine-tune all of the measurements.”
The application head covers the surface with as many passes as necessary using 12- to 16-inch rolls of PET film. Once film is applied on one side, the IG unit moves into a glass-flipping station that turns the workpiece 180 degrees horizontally and conveys it into the second film applicator to cover the other side. Finally, an operator or robot offloads the fully protected glass.
Real-time communication improves machine precision
When PDS IG engineers began to design the system in early 2018, they knew real-time communication was key to ensuring precision. The film applicator needed to leave a consistent “cutback.” This is a thin strip around the edges that remains uncovered, allowing the glass to be installed in the sash without film becoming stuck behind the frame.
“These windows range from 12 inches by 12 inches up to 96 inches by 140 inches,” Polkinghorne said. “Our equipment needs to keep that cutback the same across that area.” In addition to accurate measurement, this level of precision requires reliable motion control. In fact, it takes 28 axes of motion to properly control the conveyors and the X- and Y-axis movements of the film application head.
PDS IG needed flexible and open automation technology to ensure that the system and its various modules remained customizable. This way, they could easily integrate into customers’ existing systems and provide data for process optimization. As a result, they collaborated on the machine design with local sales and applications engineers from Beckhoff Automation. PDS IG first began using the company’s controls and components in 2011 at its Infinite Edge Technologies facility.
Don Seichter, area sales manager for Beckhoff, said this partnership has provided significant technological advantages: “Over the years, the ability to support numerous technologies in one control platform has helped PDS IG realize innovative applications that would have required multiple PLCs [programmable logic controllers] and black box technologies to come close to the same results.”
Automation adds flexibility, openness
The PDS IG window film application system relies on numerous automation technologies. For its operator interface, the system uses built-in panel PCs. These panels, which combine a 15-inch touchscreen and a PC-based controller, are mounted to small electrical cabinets hung from the machine modules. They’re able to run the human-machine interface (HMI) and a thin client to improve modularity, according to Polkinghorne. “Depending on how many modules are used, a machine line that makes IG and applies protective film could span 100 feet. The thin clients allow users to navigate HMI screens for every machine module from any control panel.”
Machine control programming for PLC, motion, I/O, safety
The machine control relies on a control cabinet Industrial PC (IPC) and automation software. The automation software combines all functionality on a real-time control platform and enables programming of the machines’ PLC, motion control, I/O and integrated safety in one environment. The CPU core-isolation capabilities of the automation software allow PDS IG to designate these functions to run on a specific core of the IPC’s processor. Before running the PLC, safety or other programs on the IPC in the field, engineers can design and test them using the object-oriented extensions of IEC 61131-3, computer science languages found in Microsoft Visual Studio, a variety of built-in function blocks and other options in the graphical editor.
Polkinghorne said the database server also allows flexibility to collect production information in SQL databases on a controller or network connected to the Internet: “We have the flexibility to give customers the right data with the right frequency so that they turn it into actionable information to enhance production.”
Further increasing efficiencies, the automation software can scan and automatically configure devices over ADS and the EtherCAT industrial Ethernet network, including third-party devices. This reduces point-to-point connections with USB cables during commissioning.
EtherCAT provides the fast deterministic communication necessary for precise measurement and film application. In particular, high-precision digital input terminals offer timestamping with a resolution of 1 ns.
EtherCAT also enables the use of TwinSAFE integrated safety technology to implement custom safety logic programmed via control programming software and to communicate safety data over the standard EtherCAT network using a “black channel” approach. “TwinSAFE allows us to implement TÜV-recognized safety in a standard control platform and display safety-relevant information on the HMI,” Polkinghorne said. TwinSAFE programs load directly onto I/O modules with built-in logic, including a safety PLC terminal, and other devices such as servo drives.
The window film application system uses a variety of motion control products for its 28 axes across the standard setup. The modules and film application head move with the help of servomotors. The servo drives provide control and power to the servomotors via single-cable technology. This has benefited multiple PDS IG applications, according to Polkinghorne: “One of our IG spacer application robots has 16 servomotors, so having just one cable for each is crucial for space savings in that solution — as well as the window film applicator.”
The servo drives also implement integrated safety through the addition of TwinSAFE drive option cards. The cards offer drive-integrated safe stop, speed, position, acceleration and rotating direction functions.
“Without hardwiring integrated safety logic, we can provide unique, flexible solutions to customers while still adhering to all safety requirements,” Polkinghorne said.
Simplified automation design doubles machine throughput
The PDS IG Equipment window film application system improved repeatability, flexibility and cycle times before going to market in the second-quarter 2019. Using the high-speed measurement of EtherCAT terminals, the applicator has a cutback precision of +/- 1/8 inch, even across the largest glass units it handles. “When applying this film on a 7- or 8-foot-long window, that consistency is pretty remarkable, especially considering how the film can stretch,” Rapp said.
Maintaining this high precision ensures IG units can be installed into the window sash without film becoming stuck when the time comes to peel it off. The flexibility and scalability of PC-based control reduced hardware requirements and offered valuable data to PDS IG and its customers. Accomplishing these results with another vendor would have required additional hardware PLCs and motion controllers.
These reduced overall costs while increasing openness, Seichter said, with “one controller without the need for a specialized, single-purpose black box.”
PDS IG was able to provide customers with insightful machine health and performance data to help them maintain the system’s high throughput. While glass dimensions vary from piece to piece, the PDS IG solution roughly doubles what is possible through other systems on the market, according to Rapp.
“Our cycle times average 25 to 30 seconds per window, so the throughput for an eight-hour shift is about 1,000 to 1,200 IG units, compared to others in the industry that produce 500 to 600 in that same timeframe,” he said. “However, with flexible and scalable technology, our expandable system could add further modules to increase per-shift throughput to 2,000 IG units — even if each one has a different SKU.”
With the ability to create increasingly comprehensive and efficient window production and finishing lines, PDS IG sees a future of continued innovation to better build and protect IG units in every circumstance, from the factory to installation.
Keywords: industrial PC, servomotor, programmable logic controller
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